SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8873f1b0a62d6af1b2823aa7d427d59b520389ec1f9d3b5e91b69c08ca288418' 
  AND token = 'mN9KeMZi0mXjizPV/Zom0wl9s6J95GnKM7+dPGn1TKc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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