SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7b84654ba19ebd92bbb0b39cabe9c2bbe347346a84dc15e70bb88700c80d5a7' 
  AND token = 'uvjH7ThCAF/IxwgLjwkIH4HM09X8vNTvvp4U5VcpVWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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