SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '7a839513cc18c98ab1f3c7796018eed1bb693542d609874dfc4f7f39a288a1e0' 
  AND token = 'ENWuociGdij4dTCTDnAxd7fc3il5ke00MuYdL/E4a6I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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