SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2fbb459d7a6472ed56528b13685b3477a045ef7ac08dc0e7eb83e24cf729202' 
  AND token = 'KsaF6gPqqED8yyEj73auj1VVScIHokqED+XrHVle3+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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