SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6b160318b50d789649cfd0e74aeca73ce8aec36c6795c6feae745fa4e0ef824' 
  AND token = '3/LD/IK15tM6fGzuVRx47CrjGK/fNqxjXXMyEPQmrHI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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