SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '093c35a5880787431405a83af0d07bd816c36e0c8d757da1f94863aa237bb692' 
  AND token = 'pvRO+knrIZE2bpTsH1Fzbr4t8hibFwl22yNnZfz2K34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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