SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '53f85b0ec5c521f6bf088d3945e384994793b312b9c8ecd706e2d520c8bc920d' 
  AND token = 'r2mZHe3CFHWrqPAbeaaa6fFaMFpDdGu+nToqZnpgF68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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