SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4f2396e342414038163719c93cb3d1b0dbc093fb93133ac28dd4d03c736e52ad' 
  AND token = 'b6XCpv4sKD56ixDJgWo+E2DFyoE1ooNBMcmokydTcBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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