SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2650efd3755d6a780913a42bf62c9572010b9dff4ffbb1822e0b14a1db9c9266' 
  AND token = '6Jr/jnBUE05kHtp4Ei3c7X47Y/CYLztFVMmp/TuKxJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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