SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '74baa133498e391ee2df2943b461018a0e32ef81d00b4af7e423562352f39a43' 
  AND token = 'rJXraF+Qk2r/ZTMJBcH8VCirABf3sYU6I2itEmaBlt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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