SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e242876c90889319e2da5163f81085efedfc0bff6d893db7b0fbe306bd3a5702' 
  AND token = 'bsz2OIr90VZfGxmdukR/nk+hoqGrJgYrHjaW2Q0Rb6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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