SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3afa28af2823f48fe0f9848670ced660f295e4aa9510c642f9d8f463024ec46' 
  AND token = 'IERC28nOueoekySbSwc3iwk5xgA+MSPytLU+jtdkKQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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