SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a7891fba8a061c70ff9b360227d4554c05d4900b89ebcdcb6dccb25ce6e6252' 
  AND token = 's7MLFh6RXdxJc3fAh0qEhbvqwuDx/2yZB2rzIB7SnjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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