SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c9ca48dd4b1e2a505960a3ac5615945a0bf26133c5a2d7f9f6bf3b7425f34c9' 
  AND token = '1iVW/fWla22gsGxHxNEWIDznsVNWVYiCKpYdkbV/BK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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