SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '296219c05b9d9cab1a78fcc5113925838ee159f9a975483052f782e630169943' 
  AND token = 'mrFUIPS9X1mQDHixhaT2LdWpmD6TNIhuExXX/LqExmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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