SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '1773b4e7e59c867f9563bb52e12305a07be2a3730d13c5e755fbb6bf92696913' 
  AND token = '3FziNUNGq9wr4HnT3Y9nDR75jDIStT42SeJgxhNVAfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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