SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3da2c2bddcd8be2795d475371e91c3df92668ce2d8948ba499664bf414ce3170' 
  AND token = '6b+iC909WqVV8A2VdJMLSKpiszvlh7+b8pcYgQXUSGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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