SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '183ae036abcaf74f149e4fab9d862a211b8cc56947d9f97d3e062661c3a435b6' 
  AND token = '5ILOgqvx566kPHKYqiKrMpqk1vEtAMuUcwajqANnpps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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