SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bfc41fed9e0af2b3fad7426b80f3433ef2a9e254a15d67701f3395cf62051d6' 
  AND token = 'RE647VdkSsZPwhJJFctFFSUjd+O9I3tNdiZj884wXhY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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