SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41d35b4e3b341320ad9c30103710e70579737de310e52d40ef2c3b0ed7a5470c' 
  AND token = 'crchEwBkDMgyBmrVIDOOUysoBmusOm7WXbZVObgYcoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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