SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8edda4ff22bda37a3857da9545cd7c964f869861af0b46e810cbc8ade4d9977' 
  AND token = 'QAyHZBNns1kTncpcKnmSV9dQmZsQR/zvLiIS9kHm4eo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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