SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cabcd82220e802f57701e34fee6c3a0217147b2f42d8df81b52498a74df9abe2' 
  AND token = 'InBBr6q/owDZjFppqvmGq44p9t2LuyV8QeU8a/l+Sho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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