SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39f7088de7fcbd502c31e35897533fd8b81545f66cd52b1f104a629eef19447a' 
  AND token = 'JohgKR7EoVGuunsvrK5Ht9Lhhs4Ivu9lQERd6ixTVSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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