SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86f7667433d94e3b0fab5fe8c9208a423bfbbb2e53e1ff5350d1a560a5475572' 
  AND token = '/qKjUv4NrgJAzkUmBdndUIhP8xlL5KLYFbAQf+hJvOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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