SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ad645a7510fd780943f6694df0610b27886fc2b6f37ec677f9c888b37e7649d' 
  AND token = 'DQy7+CfpgKj5Bv7z3xnK9HjoZ5unyGPGVy7NPj8+OG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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