SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3e8ec4830808fee4999ef3e710d5ad077bf5dd8f0c128d186f37459f04aa5cc' 
  AND token = 'DZybWN8Bjfrm4RQdLw/99oTHkMdgI+GVJ9oqIwzafL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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