SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b24716ba308468f2ca8a164ddb4b2aebb563123289ac57035cf5f25cb1fc17e0' 
  AND token = 't7UVSc/21nLPee15jPq2xGreHWL9CyAVSLiVJNwPga4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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