SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58924cebb795f9782124db91a0c8212bd8c7ecbaa76694df9b0c180ec040de72' 
  AND token = '8eV24juYA0FzzCSzwQft/IktTP7HSS4MKxcEBtPYYC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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