SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a12e0b0e7eb9709e741e21353f1718f71af6d3bda641e2adb0a4cc092910623' 
  AND token = 'MMpzBtl6gxXpdVp1ePgDvnU525H3pMdOXXa7vqTC1Xs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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