SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8684d7ca18abe7282d22937c66d0a29301881365d29d75ece03b42edaa7631f9' 
  AND token = 'BHxHOddA0cgthH4wFKMr8JpbtVEnmJNwBp+ji49dL4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}