SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd9683224f73f1e14545b4c5a84a039fbb5ef22066a066f22e2e1e9282ae5cbf' 
  AND token = 'gf0j+Czb7to00yy1wVtjvclh3IcGgfVBJOWJ/qncrM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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