SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cb2a959010dd594e761f358434a09fa1c781c6894d4eefcbbbf33d4f6290831' 
  AND token = '4LibxKYdZc/MdjEaDIWwdOpQ4nrlrNLhW+V4iqnm50w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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