SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fc3766b1e0634e76cd00849cbd2939237c391201f6b36148f9058cbec01f576a' 
  AND token = 'YKkMJBI5mbbjXx+FxmnxmAmOjbGQmVRz1l0J0le0hD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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