SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '7a430e8bd158a2c996d26825cf2766cecfdb2fd4ccc3ac883f0b626ff6fbc269' 
  AND token = 'xiXLn3SER3Z5jAhAXuFDid5J1a1UcNk+362AiBzljrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}