SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb05366046d9c93142ba6f8ba2a62408b1b9d4c9efb07d549f101fa8a29ba4db' 
  AND token = 'oUGmt50CCBOowZ4YgxrMi6z+/ZsC1N1QtOBewwiXdXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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