SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6afa45b877557133d35a6373691af1f01e2305a95fcf9cad92b680e138186450' 
  AND token = 'KVSt2pZTs9ZBrJ+mwMdB+3Av/80FMYFdBIMP5auMbPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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