SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14cc8a97b2a248da77683a9939d61ff050041139202d44aa303ce5887ba18275' 
  AND token = 'birHQ+Sdm9m5IovwIc1qG8JDe3x83qdmE2LCTOT5OBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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