SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7767d0dbfa948bc5761f08e997303517fec42ddcd1d46e4a070746ab81a313d' 
  AND token = 'MbW+0bvXlM/mGvn0svRLOqmy9jKdau92SVAvCGcIydM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}