SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9b45fb716fab8595aaeb344a2f54cc69d0317bd18cd8c16b5d10e7440476e4d' 
  AND token = 'AMCZoYbkq2VjzvRxt+iAgYXNRh+DKildAty/gqUrRnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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