SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4caffab32dd6ee796125f8e92d9dc0cce60700c779fc812dab30c4d986bc790' 
  AND token = 'ecWzcjVP2xhcwoQamipiisdgQaHGAWjJvwQoqVHhxQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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