SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5928265f31cb61cf6a2fbe5c90df17184caec3a819903dae20c10456952d459' 
  AND token = 'BnUcJXfaXLP7QTR+cZHnie1aDwPH/sVUaDeAR/MNdtk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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