SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba6ffc02f51707b333d1355edffafaaa42efce1c7275139c4d8a0ec4f53bf453' 
  AND token = 'VtcvM7sOGbAqzLqcGFBCIr47v+9mTUNKRfAoQ9oZvH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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