SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '312b9235cd42a2ea54dea7b4ed1a7036de16376c3892b02a52470f18da497212' 
  AND token = 'XKI1kOKQ01bbxKGAIBUuiX7PClmMP0YE0ZEKVeF2+9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}