SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5a9e6964fd45dbdade83452df45d5e38669e6f108a3150c877b376e79cf6d4b' 
  AND token = 'X944INICYeKkF0YJsiW/ftBGL9Gb/RLxaDA24moERlQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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