SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a77e5867a0d18c0097cbda4baaee04c83ae0f9cad50d775073bd4000b0ccd42' 
  AND token = 'emrlzhRprMDHnDb4zDcJ5NdJO5f3BaG+80mFaAOxpk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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