SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a9be0c976fbc379d4567fa46a3d3db65391883b66fde1ff75698302834326bb1' 
  AND token = 'sRFQhaqe56+KmSpsZrrF81MiJ4eAGRsY45bKfnnlXqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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