SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '768a334165d1c95c6f596f38ba943e019cb51f9f6aa72e5931b2e56623c7708c' 
  AND token = 'JjwxvIzNS+9o6xJOverDQHZFPYcvZdya4pbA0pj3iUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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