SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '997bdacb42be27aa11c8e2ff11405453c75a7b58ec099cc278af350fb262ca52' 
  AND token = 'NxleSQnMRDCQv2Ln7EMBz5TcMf1erKG3v/HlxENohGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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