SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfacc317445d048c5e7516819c869582511c386d233d3c6707ab60d6ac798edf' 
  AND token = 'u9lpMDxcraAiWhYwdYbwpWvm+AXGdYkjyB/+pEYItOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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