SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5a057c4151ea3cb6b5b3cfad66a22f38e64212f5f98d5f5bd3c0b9e6206a288' 
  AND token = 'VWIIJIwUVPZ5BODm/Fa/gbQXk+JRftAMF0LO98vzAxU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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