SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73f14807f992528f243f3f277cb2b840ee6b9ed4dafecf78b3aa3783550a90f4' 
  AND token = 'BFt+OhrcuKxQiL+HjrdEEoqjjknXLYoLz/S4lgSXOqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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