SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '966b1a0b937781e1b931a00608a702a726843c951b5cd2b546594da455ac930a' 
  AND token = '8MMstVM/DUOVHBWs8gTwGiCfD7N6hqDdqqZa/FkabNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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