SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f50de11f775e59c5e691991942673582a64e09c2bc29a67d2e7f78da42c3333' 
  AND token = 'If60uPYTuQuycP59bSDmB9XSckMlYHihpYdOpsBIIXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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