SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c47755eb5d8a07e1e7eb0a9c5e934574adefebf7294b4240306c988d6bc0674b' 
  AND token = 'NH4mNtIfPGEH4QCcXxco1cpJFrhwQ0uEo+ltoi6DbZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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