SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '505bb257a256777fac5a6ad79b8719482250c0536850b0fb9d311b7e395491f8' 
  AND token = '3Q/7MH8ya2+3rzvRN1i2+vNEIGYOjvztg/Ulrdo0igw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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