SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4c0495734ef9547058eb8451167273466451e6efd92541349f8e6477d2ba8cd' 
  AND token = 'Rm6JjS+3WlyonS/i3vRsaoK0ntW9hmgSEaKyvJTtHII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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