SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e85a9707995c6632ecc68ee4a10883132d634946bebb86da5470e3f5bd74e31b' 
  AND token = 'p7IiPVm6h633WkX01aFBJTnjGdti49r3vtxdliipAiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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