SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84df0508e43296d5cafb13824a511141a1ce4df4494e8ed520a073f99cbf89a2' 
  AND token = 'm4Q5Fkl0ejpQUUXuikmhQAFn1UgUtSRieyoRB0PCywo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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