SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad143d1542a7311a8a708959b50ea5de9bfd2b803f95df5bce7c0b598c5cbbd2' 
  AND token = '1hKdzL5GTgjyv+zWQD81mTdp74HWUb6isFNwVjkYMV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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