SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6cfb1e2b1d562d948c674bd752fce7b40db12c36645f6edd47418e26c2207d3' 
  AND token = '/z+RiAhSQwEFlZO1tFnWzdZvsfs+JpfJTjZnGJ1KGbs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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