SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '797fac7f05212632cc5667e7dc61f7471906375bd67ac408957fe7941d57e667' 
  AND token = 'NxQAqMut+hfMpD/UpYawj+O5o5uCvCQrf6tCbB4AM54=' 
  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"
    }
  }
}