SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92a16498a86881d15720866ef4eca160075a2562141bb0573834902da64d435b' 
  AND token = 'm/RBt/UYD1LpJ3ZsL5qzNvoTPJEYdQyuBvATXNYUsoM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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