SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8025b13540ec7e91eb598693adb26dc25218155f195fe6cf0e66b474be32096d' 
  AND token = 'M1FZdWRxhFK1mdgbsXymIIRihBZUeS4pRDpKaRmR+3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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